Evolution of Structure in Deformed Single Crystals of fcc Metals at Heating

Abstract

AbstractThe paper deals with conditions resulting in formation of dislocation structures of different types as well as with the change of these structures at subsequent heating which ends in the recrystallization center formation and growth. The measurements were carried out on single crystals of fcc metals. The principal experimental technique was electron microscopy including the annealing of deformed foils directly in the column of electron microscope with accelerating voltage 150 and 1000 kv. Special attention is given to research of the initial stage of recovery in dislocation structures during annealing — the dislocation recovery as the most universal mechanism occurring at any type of structure even when polygonization and recrystallization are hampered. Studies of initial recrystallization stages were mainly carried out while annealing the deformed single crystals of copper. A high degree of local lattice curvature is shown to be a necessary condition for nucleation, and mechanism of the nucleus formation in regions of a high local curvature differs according to the type of the dislocation structure formed during deformation.